import java.util.ArrayList;
import java.util.List;

/**
 * @author: 最帅的的乐乐
 * @date: 2024-05-14 10:17 星期二
 * @motto the harder, the luckier。
 * 递归
 * Completed at @date: 2024-05-14 11:19
 */

public class _22_GenerateParenthesis {
    List<String> res = new ArrayList<>();
    public List<String> generateParenthesis(int n) {
        if(n <= 0){
            return res;
        }
        getParenthesis("",n,n);
        return res;
    }

    private void getParenthesis(String str,int left, int right) {
        if(left == 0 && right == 0 ){
            res.add(str);
            return;
        }
        if(left == right){
            //剩余左右括号数相等，下一个只能用左括号
            getParenthesis(str+"(",left-1,right);
        }else if(left < right){
            //剩余左括号小于右括号，下一个可以用左括号也可以用右括号
            if(left > 0){
                getParenthesis(str+"(",left-1,right);
            }
            getParenthesis(str+")",left,right-1);
        }
    }
    public static void main(String[] args) {
        _22_GenerateParenthesis solution = new _22_GenerateParenthesis();
        int n = 3; // 设置括号对数
        List<String> result = solution.generateParenthesis(n);

        // 打印生成的括号组合
        System.out.println("Generated Parentheses for n = " + n + ":" +result);
    }
}
